Revert of Create RtcpDemuxer

webrtc/call/rtp_packet_sink_interface.h

Index: webrtc/call/rtp_packet_sink_interface.h
diff --git a/webrtc/call/rtp_packet_sink_interface.h b/webrtc/call/rtp_packet_sink_interface.h
index 0b3e64e313468d5b3ebe95bb5f913f726906d436..900ca354d4c106c3990ca7a560837a387847a8bb 100644
--- a/webrtc/call/rtp_packet_sink_interface.h
+++ b/webrtc/call/rtp_packet_sink_interface.h
@@ -14,10 +14,10 @@
 
 class RtpPacketReceived;
 
-// This class represents a receiver of already parsed RTP packets.
+// This class represents a receiver of an already parsed RTP packets.
 class RtpPacketSinkInterface {
  public:
-  virtual ~RtpPacketSinkInterface() = default;
+  virtual ~RtpPacketSinkInterface() {}
   virtual void OnRtpPacket(const RtpPacketReceived& packet) = 0;
 };